1. Field of the Invention
The present invention relates to a solid-state image sensor and, more particularly, to a solid-state image sensor used in image-observation of an object when an image observation of the object and an analysis at a specific portion of the object are simultaneously performed, and an analysis system using the same.
2. Related Background Art
An analysis of an object often requires not only observation of its image, but also measurement of spectrum energy characteristics or the like of a given portion of that image. As a system that makes such analyses (that can simultaneously obtain an image and spectral characteristics), the one described in Japanese Laid-Open Patent No. HEI 1-320441 is known. More specifically, this analysis system (luminance calorimeter) is comprised of a plate 103 with an aperture 103xe2x80x2 on which an image of an object 101 is formed via an objective lens 102, a half mirror 111 which is inserted between the plate 103 and the object 101, and serves as a split device for partly reflecting light emitted from the object 101, a TV camera 117 as an image sensor for shooting the image of the object 101, which is reflected by the half mirror 111, a spectroscopic device 106 for spectrally resolving the light emitted from the object 101, which has passed through the plate 103 via the aperture 103xe2x80x2, a detector 108 for detecting the spectrum obtained by the spectroscopic device 106, a data processing circuit 119 for processing the spectrum data, a signal superposing circuit 118 for superposing an analyzed data signal output from the data processing circuit 119, and an image signal output from the TV camera 117, and a monitor 110 for displaying on the basis of the signal output from the signal superposing circuit 118, as shown in FIG. 13. The analysis system splits light rays emitted from the object 101 using the half mirror 111, so that the one is used to shoot a two-dimensional image, and the other is used to detect spectral characteristics, thereby simultaneously displaying two-dimensional image b of the object, and spectral characteristic data a of a given portion of the object on the monitor 110.
However, the conventional analysis system suffers the following problem.
First, the monitor 110 displays marker c at the sampling position of the spectral characteristics in addition to two-dimensional image b and spectral characteristic data a of the object. The display position of marker c often has a deviation from the position of the object 101 where the spectral characteristics are actually detected, i.e., a measuring spot 104. That is, display of marker c is set in-correspondence with the position of light rays that have passed through the aperture 103xe2x80x2, but the measuring spot 104 of the spectral characteristics has a deviation from marker display position c due to positional deviations of the light-receiving surfaces of the half mirror 111, TV camera 117, and the like.
Second, the half mirror 111 is used to split light rays. However, it is hard to manufacture a half mirror 111 with uniform wavelength characteristics of transmittance, and the spectral characteristics of light emitted by the object 101 change when they pass through the half mirror 111. For this reason, accurate spectral data for the object 101 cannot be obtained, resulting in poor measurement accuracy.
Third, the aforementioned analysis system can analyze if the object emits light rays, but cannot be applied to measurements of X-rays, electrons, or ions. That is, light rays can be split by the half mirror, but X-rays, an electron beam, ion beam, or the like cannot be split by the half mirror. Therefore, the system of this type cannot analyze and measure an X-ray image and the like.
The present invention has been made to solve the aforementioned problems, and has as its object to provide an analysis system which can analyze and measure radioactive rays and the like, and can obtain accurate analysis characteristics while confirming the analysis position, and a solid-state image sensor for obtaining an image to be analyzed for that system.
A solid-state image sensor of the present invention is a solid-state image sensor which converts an image that represents the spatial distribution of light such as visible light, infrared rays, ultraviolet rays, or the like, radiation such as xcex1 rays, xcex3 rays, X-rays, or the like, an electron beam, ion particles, or the like incident on an image receiving surface into an image signal by pixels arranged in a two-dimensional matrix on a substrate. This solid-state image sensor is provided with an aperture which extends from the pixel matrix area through the substrate, and a signal transfer path for reading an image signals from each pixel kept clear of the aperture.
With this arrangement, a solid-state image sensor with an aperture around which pixels are arranged can be provided. Of these energy beams such as light, radioactive rays, electrons, ions, or the like, which have reached an image receiving surface, energy beams that have reached this aperture portion pass through the aperture.
Preferably, an image sensing unit of the solid-state image sensor is divided into at least two regions by a boundary including the aperture, and the solid-state image sensor is provided with individual registers each for respective region to read image signals from the respective pixels by transferring the image signals.
With this arrangement, the image sensing unit is divided into at least two regions by the boundary including the aperture, and these regions respectively have individual registers (normally, horizontal transfer registers). That is, this arrangement is similar to a state wherein at least two independent image sensing units are present to sandwich the aperture therebetween. When an aperture is formed at the center of an image sensing unit in a conventional solid-state image sensor, the image sensing unit of which is formed by a single region as a whole, it is hard to vertically transfer signals beyond the aperture portion. As a result, pixels which cannot undergo vertical transfer, i.e., normally pixels within a predetermined width above the aperture, become invalid pixels from which an image signal cannot be read. Since the present invention divides the image sensing unit into a plurality of regions by a boundary including the aperture portion, charges need not be vertically transferred beyond the aperture portion. That is, extra invalid pixels can be prevented from being produced.
Furthermore, the solid-state image sensor is preferably back-incident type solid-state image sensor which is provided with electrodes for transferring image signals from the pixels on an opposite side of the image receiving surface. The back-incident type solid-state image sensor can assure a broader effective entrance surface than a front-incident type solid-state image sensor, since its image receiving surface is not covered by electrodes, and also has higher conversion efficiency of incoming energy and higher sensitivity than the front-incident type.
On the other hand, an analysis system of the present invention comprises one of such solid-state image sensors, an imaging system, inserted between the image sensor and an object to be measured, for forming the image of the object on the image receiving surface of the image sensor, an analysis system for analyzing a characteristic of the object from energy beams that have passed through the aperture, and converting analyzed result into an analysis data signal, and a display device for displaying an image corresponding to the image and the analysis data on the basis of an image signal output from the image sensor and the analysis data signal output from the analysis device.
With this arrangement, the characteristics of the object are analyzed by the analysis device from energy beams that have passed through the aperture portion of the solid-state image sensor with an aperture. Therefore, the aperture position of the output image from the solid-state image sensor reliably matches the analysis position.
Furthermore, the analysis apparatus preferably further comprises marker signal generating device for generating a marker display signal to be superposed on a signal portion corresponding to the aperture in the image signal in synchronism with the image signal output from the image sensor, and the display device simultaneously displays a marker indicating an analysis position of the analysis device on the displayed image on the basis of the marker display signal output from the marker generating device. With this arrangement, the analysis position can be confirmed more easily.
The object may be set to be movable relative to the image receiving surface of the solid-state image sensor. Alternatively, the image receiving surface may be movable relative to the object. With these arrangements, the analysis position of the object can be easily scanned.
The analysis device can use a spectroscope, energy analyzer, or mass analyzer, and preferably further comprises an electron optical system for decelerating electrons or ions that have passed through the aperture of the solid-state image sensor, when the electrons or ions are to be measured. Alternatively, the analysis device may comprise a streak camera.
The imaging system may comprise an optical system including an optical lens, prism, or mirror, and at least one of the components of the optical system may be movable relative to the object or the image sensor. Alternatively, the imaging system may have a deflector for forming an arbitrary magnetic field or electric field between the object and image sensing sensor.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.